在将节标题添加到我的应用程序中的一个表之前,我能够使用 commitEditingStyle 函数删除行。我决定实现部分标题,以便用户更轻松地查看按日期添加到表中的项目。我测试了这个功能,它工作正常。但是现在尝试删除一行会导致崩溃:
-[UITableView _endCellAnimationsWithContext:], >/SourceCache/UIKit_Sim/UIKit-2903.2/UITableView.m:1330 中的断言失败
我是 obj-c 开发的新手,不愿意添加这些部分,因为我知道这会增加代码的复杂性,我花了一段时间才弄清楚。但我想这就是你学习的方式。
下面是 cellForRowAtIndexPath 函数的代码:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath: (NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
AgendaCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[AgendaCell alloc]
initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier];
}
NSString *strDate = [dateArray objectAtIndex:indexPath.section];
NSMutableArray *dateSection = [tempDict objectForKey:strDate];
NSManagedObject *object = [dateSection objectAtIndex:indexPath.row];
cell.sessionNameLabel.text = [object valueForKey:@"sessionname"];
cell.sessionNameLabel.textColor = [UIColor blueColor];
cell.sessionDateLabel.text = [object valueForKey:@"sessiondate"];
cell.sessionDateLabel.textColor = [UIColor brownColor];
cell.sessionTimeLabel.text = [object valueForKey:@"sessiontime"];
cell.sessionTimeLabel.textColor = [UIColor brownColor];
return cell;
}
这是我的表格刷新功能的代码:
- (void) refreshTable
{
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Sessnotes" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
[fetchRequest setPredicate:[NSPredicate predicateWithFormat:@"agenda == 'Yes'"]];
// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"sessiondate" ascending:YES];
NSArray *sortDescriptors = [NSArray arrayWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
NSArray *results = [self.managedObjectContext executeFetchRequest:fetchRequest error:nil];
[self.refreshControl endRefreshing];
self.objects = results;
if (results.count == 0) {
NSString *message = @"You have not added any sessions to your planner.";
UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"Notification"
message:message
delegate:self
cancelButtonTitle:@"Ok"
otherButtonTitles:nil,nil];
[alertView show];
}
else if (results.count > 0){
tempDict = nil;
tempDict = [[NSMutableDictionary alloc] init];
NSString *strPrevDate= [[results objectAtIndex:0] valueForKey:@"sessiondate"];
NSLog(@"strPrevDate value is: %@", strPrevDate);
NSString *strCurrDate = nil;
NSMutableArray *tempArray = [[NSMutableArray alloc] init];
//Add the Similar Date data in An Array then add this array to Dictionary
//With date name as a Key. It helps to easily create section in table.
for(int i=0; i< [results count]; i++)
{
strCurrDate = [[results objectAtIndex:i] valueForKey:@"sessiondate"];
if ([strCurrDate isEqualToString:strPrevDate])
{
[tempArray addObject:[results objectAtIndex:i]];
}
else
{
[tempDict setValue:[tempArray copy] forKey:strPrevDate];
strPrevDate = strCurrDate;
[tempArray removeAllObjects];
[tempArray addObject:[results objectAtIndex:i]];
}
}
//Set the last date array in dictionary
[tempDict setValue:[tempArray copy] forKey:strPrevDate];
NSArray *tArray = [tempDict allKeys];
//Sort the array in ascending order
dateArray = [tArray sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];
}
[self.tableView reloadData];
}
以下是 commitEditingStyle 函数的代码:
- (void)tableView:(UITableView *)tableView commitEditingStyle: (UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
//add code here for when you hit delete
NSManagedObject *object = [self.objects objectAtIndex:indexPath.row];
NSManagedObjectContext *context = [self managedObjectContext];
[context deleteObject:[context objectWithID:[object objectID]]];
NSError *error = nil;
// Save the object to persistent store
if (![context save:&error]) {
NSLog(@"Can't Save! %@ %@", error, [error localizedDescription]);
}
NSMutableArray *array = [self.objects mutableCopy];
[array removeObjectAtIndex:indexPath.row];
self.objects = array;
[tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
}
}